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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

High resolution portable holocamera

High resolution portable hologram recording camera with pulsed ruby laser light source and rechargeable storage batteries as self contained power supply

Close, D. H.↗
NASA NTRS1971

Research investigation directed toward extending the useful range of the electromagnetic spectrum

The lifetimes and fine structure of He(-) were studied using time-of-flight techniques and quenching by a static axial magnetic field. Using level-crossing spectroscopy the hyperfine constants A and B and the lifetime of the 3 2P3/2 state of Li-7 were measured. Polarization of the Ru 7S level was created as a first step in determining the hyperfine structure of the alkali excited S state. The parametric interaction between light and microwaves in optically pumped Rb-87 vapor were investigated. Measurements and analyses of transitions in formaldehyde and its isotopic species and in the lowest two excited vibrational states of H2CO were also made, as well as of transitions in furan, pyrrole, formic acid, and cyanoacetylene. The Hanle effect was studied in the NO molecule, and RF oscillators were developed with flat, wideband output to observe excited state hyperfine transitions at zero field. Data was generated on the time-dependent behavior of photon echoes in ruby. Stimulated Raman scattering was studied in atomic Tl vapor. A Q switched, temperature-tuned ruby laser was developed which operates between 6934 and 6938 A. The frequency shift due to resonant interaction between identical radiating atoms was calculated.

Hartmann, S. R.↗
NASA NTRS1972

Research in nonlinear optics

A theoretical investigation revealed that a steady state mode-locked solution appropriate to ultrashort pulses is induced by Kerr liquids. An experimental investigation using a Q-switched ruby laser passively mode-locked by the insertion of a Kerr liquid verified the theory. Pulses of about 10 to the -11th power sec were generated when the relaxation time of the liquid was temperature tuned to approximately 10 to the -11th power sec.

Yariv, A.↗
NASA NTRS1971

Raman scattering cross section for N2O4.

Measurement of the Raman scattering cross section for N2O4 at a Raman shift of 7.3 micron, using a Q-switched ruby laser as an excitation source. The cross section for N2 at a Raman shift of 4.3 micron was also measured and compared with the value given by Leonard (1970).

Chen, C. J.↗
NASA NTRS1972

Optical Production and Detection of Ultrasonic Waves in Metals for Nondestructive Testing

Ultrasonic waves were produced by striking the surface of a metal with the focused one-joule pulse of a Q-switched ruby laser. Rayleigh (surface) waves and longitudinal waves were detected with conventional transducers. Optical methods of detection were tested and developed. Rayleigh waves were produced with an oscillator and transducer. They were optically detected on curved polished surfaces, and on unpolished surfaces. The technique uses a knife edge to detect small angle changes of the surface as the wave pulse passes the illuminated spot. Optical flaw detection using pulse echo and attenuation is demonstrated.

Morrison, R. A.↗
NASA NTRS1972

A description of the lunar ranging station at McDonald Observatory.

The equipment of this station which has been in operation since the deployment of the first corner reflector by the Apollo 11 astronauts. The McDonald 2.7-m telescope is used for both transmission and reception of pulsed ruby laser light during three 45-minute daily laser runs about three weeks in a month. The present laser pulse width, timing system, calibration procedures, and signal levels are designed to achieve ranging with an accuracy to 1 nanosecond. The data rates obtained since September, 1970, are consistent with the scientific commitments of the lunar ranging program. Most of the over 200 acquisitions obtained have an accuracy to better than plus or minus 30 cm. Details of the telescope matching optics, guiding and timing equipment, and calibration procedures are discussed. Representative lunar range data are included.

Silverberg, E. C.↗
NASA NTRS1972

Internal upconversion and doubling of an optical parametric oscillator to extend the tuning range.

Efficient extension of the tuning range of a 1.09-1.95-micron parametric oscillator to 0.435-0.975 microns by upconversion and doubling internally to the oscillator cavity is reported. Unlike previously studied external mixing, internal upconversion and doubling yielded uniform powers of 30 and 60 kW, respectively, over the entire extended tuning range with an unfocused 2-mm ruby laser pump beam of 750 kW.-

Campillo, A. J.↗
NASA NTRS1973

Photographic laboratory studies of explosions.

Description of a series of cinematographic studies of explosions made with a high-speed rotating-mirror streak camera which uses a high-frequency stroboscopic ruby laser as the light source. The results obtained mainly concern explosions initiated by focused laser irradiation from a pulsed neodymium laser in a detonating gas consisting essentially of an equimolar mixture of acetylene and oxygen at an initial pressure of 100 torr at room temperature. Among the most significant observations were observations of a spherical blast wave preceded by a Chapman-Jouguet detonation which is stabilized immediately after initiation, the merging of a spherical flame with a shock front of the blast wave in which the flame is propagating, the division of a spherical detonation front into a shock wave and flame, and the generation of shock waves by a network of spherical flames.

Kamel, M. M.↗
NASA NTRS1972

Disproportionation of Fe2SiO4 to 2FeO plus SiO2 at pressures up to 250kbar and temperatures up to 3000 C

A sample of Fe2SiO4 (spinel) at approximately 250 kbar in a diamond anvil press was heated to approximately 3000 C for a duration of some ms using a focused light beam from a pulsed ruby laser. After quenching and unloading, X-ray diffraction patterns indicated that the portion of the sample that had been heated contained wustite and stishovite. A sample of Fe2SiO4 (fayalite) at approximately 200 kbar in a diamond anvil press has been heated to 800 C for 20 min in a furnace. After quenching and unloading, the sample was found to have concentric zones with the fayalite phase at the lowest pressure, the spinel phase at the intermediate pressure, and a dark region at the center where the pressure was highest. An X-ray diffraction pattern of the dark central region indicated the presence of wustite. A microprobe analysis of a sample produced by a similar procedure indicated that SiO2 is apparently evolved along with wustite but is not sufficiently crystalline to be detected by X-ray diffraction.

Bassett, W. A.↗